Patent document 1 discloses a lithium secondary battery having a negative electrode using silicon oxide as a negative electrode active material.
Also, Patent document 2 discloses a method for discharging a non-aqueous electrolyte secondary battery using silicon oxide containing lithium as a negative electrode active material. More specifically, Patent document 2 discloses a method for controlling a discharge of a non-aqueous electrolyte secondary battery by discharging it in a range where the voltage of the negative electrode with respect to lithium reference electrode is not more than 0.6 V.
Also, Patent document 3 discloses a non-aqueous secondary battery in which the negative electrode active material is a silicon compound which is represented by MxSi and in which the crystallinity calculated by differential scanning calorimetry is in a range of 10 to 60%. Also, it discloses a charge method in which this non-aqueous secondary battery is used and in which the charge is finished when the potential of the negative electrode with respect to metal lithium is a potential higher than 100 mV.
Also, Patent document 4 discloses a method for using a lithium secondary battery in which an electrode having an active material layer containing silicon on a collector is used as a negative electrode. More specifically, it discloses a method for using the battery in which it is charged and discharged at a negative electrode potential of 0.8 V or less (vs. Li/Li+) except for the first charge.
Also, Patent document 5 discloses a secondary battery which has a negative electrode containing silicon (Si) as a constituent element in which a molar ratio (Li/Si) of lithium atom to silicon atom (Li/Si) is 4.0 or less.